A number of dispensers exist in the prior art for dispensing paper toweling and the like. Some of these dispensers are of the "center-pull" type wherein a web of toweling or other sheet material is pulled from the center of a coreless roll through a nozzle or other restrictor element forming a restricted passageway. Assuming that the individual sheets of toweling or the like are connected by perforated lines, as is common, the nozzle or other restrictor element will resist pulling of the sheet material by the user, thus breaking an individual sheet from the remaining web along the perforated line interconnecting same. U.S. Pat. No. 4,905,868, issued Mar. 6, 1990, illustrates a representative paper towel dispenser of the type just described.
U.S. Pat. No. 4,905,868 teaches the use of a conical funnel having a exit hole larger than the entrance hole thereof which provides an exit for paper towels being dispensed. The entrance opening and exit opening of the conical funnel are dimensioned such that a first paper towel will separate from a following paper towel along the perforation boundary therebetween when a leading portion of the following paper towel exits from the exit opening in the funnel.
Paper towels are made available with widely differing physical characteristics. For example, paper towels are manufactured and sold having different basis weights, bulks, tear strengths, and physical dimensions such as thickness. It has been found that a single nozzle or funnel size does not allow or provide for efficient dispensing of all towels. Paper toweling having a certain physical characteristic might dispense and tear properly after passing through the nozzle while paper toweling falling within a different physical characteristic range may not dispense properly.
U.S. Pat. No. 4,905,868 recognizes the fact that some nozzle adjustment must be made to accommodate a wide variety of paper towels. In the patent an attempt is made to solve the problem by providing the exit portion of the funnel or nozzle with one or more narrow neck portions which may be removed (by cutting, clipping, or breaking, etc.) in order to adjust the inside diameter of the nozzle exit opening. That is, detachable sections are included at the end of the nozzle of U.S. Pat. No. 4,905,868 to accommodate different sizes and thicknesses of paper towels used. The patent also makes a general statement to the effect that "varying" of the exit opening may be accomplished with "adjustable structure such as a collapsible funnel which may be moved to increase or decrease" the opening and then "locked into place." There is no teaching of such adjustable structure.
U.S. Pat. No. 4,905,868 merely addresses the matter of changing the size of the nozzle exit opening. It has been found that merely changing the size of the exit opening will not in all cases modify the nozzle sufficiently to adapt it to use with a wide variety of towels. Furthermore, in the embodiment of the invention disclosed in the patent, cut portions of the nozzle, once removed, are gone permanently and cannot be reattached. Thus, once the nozzle has been severed to accommodate one type of towel it cannot again be used efficiently with another type of towel calling for a smaller nozzle exit opening and longer nozzle.
The following patents are also known: U.S. Pat. No. 4,262,816, issued Nov. 21, 1981, U.S. Pat. No. 4,651,895, issued Mar. 24, 1987, U.S. Pat. No. 4,648,530, issued Mar. 10, 1987, U.S. Pat. No. 4,534,491, issued Aug. 13, 1985, U.S. Pat. No. 4,219,129, issued Aug. 26, 1980, U.S. Pat. No. 4,171,047, issued Oct. 16, 1979, and U.S. Pat. No. 4,180,160, issued Dec. 25, 1979. The patents just listed disclose various dispensing devices for dispensing sheet material, such as towelettes. The patents disclose various types of restrictors for separating individual sheets when pulled by a user. One of the patents, U.S. Pat. No. 4,651,895, discloses the concept of employing different dispensing aperture shapes.